1. Technical Field
This invention relates to the field of an apparatus for applying pulling force. More specifically the invention relates to an apparatus for placement of conductive wire.
2. Background Art
Supplying buildings with electricity and communications involves threading lines, or cable, through conduit. Typically, the path that cable must travel through conduit includes changes in elevation and turns around corners. Generally, the procedure used to run cable involves first threading lightweight flexible lines through the entire length of conduit. Heavier lines are then pulled through, by attaching them to one end of the lighter line and pulling the lighter line through at the other end of the conduit. This procedure may need to be repeated until a line is threaded which can bear the weight of the target cable, when is then attached and pulled through.
To thread heavier lines, lighter lines must be pulled through first. The pulling force required can be significant depending on the weight of the heavier lines and distance traveled. The pulling force can also increase with the bends and turns in the conduit. Thus, there is a need to substitute machine force for human force to reduce the human effort required in this procedure.
Others have substituted machine force for human force in pulling cable through conduit. Oleson, U.S. Pat. No. 3,190,616, discloses a cable threading apparatus. Newell, U.S. Pat. No. 3,968,952, discloses an assembly for pulling a line. Straight, U.S. Pat. No. 4,270,734, discloses a portable wire puller. Lucas, U.S. Pat. No. 4,456,225 discloses a cable pulling apparatus. Carter et al., U.S. Pat. No. 4,497,470, discloses a powered cart mounted cable puller.
Each of the named apparatus includes a dedicated motor; however, dedicating a motor in most cases adds bulk, weight, and cost. Therefore, the need to substitute machine force for human force in pulling wire without significant bulk, weight, and cost is not met by these apparatus.
One solution to the problem of bulk and weight is to adapt existing multiple-use motorized tools to provide the force for pulling wire through conduit. A common multiple-use motorized tool likely to be available to technicians, who run cable, is the hand-held power drill. Others have applied the use of hand-held power drills for winding. Cole, U.S. Pat. No. 4,196,864 discloses a line winding tool set. Sossamon, U.S. Pat. No. 4,951,890 discloses a drill-operated adapter for unwinding fishing lines from reels. Jones, U.S. Pat. No. 5,149,056 discloses a wire puller for electrical conduits.
These apparatus attach to a power drill, utilizing the power of the drill to pull cable and wind it onto various sized and shaped spindles. However, they are often insufficient for use with the various weights and lengths of cable threaded through conduit. Further, these apparatus share a problem, in that an operator must exert differing degrees of stabilizing force to hold the drill during the winding process. In summary, the prior art apparatus have proven to be cumbersome, and to be very limited in the capacity of line that may be wound onto their spindles.
Thus, it can be seen from the above discussion that it would be an improvement in the art to provide a line puller which can be driven by a multiple use motor so that the weight and cost of the apparatus is minimized. Also it would be an improvement if the line puller could be positioned such that the operator does not have to exert a stabilizing force while the wired is pulled, and is not limited in line winding capacity.